The invention relates to a mechanically controlled switch with automatic opening for a protective limiting device, said switch comprising:
a housing having a breaking chamber provided with fins for fractioning the arcs, PA1 a power switch placed in this chamber and having at least one fixed contact and a mobile contact which is actuated by a pushbutton and which is subjected to the action of a fixed pressure spring tending to apply it against the fixed contact, PA1 a coil which is serially connected with the switch in a circuit and is adapted to attract a magnetizable striker when the circuit has passing therethrough a short circuit current, PA1 a control device having a mobile part which cooperates by pushing with the pushbutton to move the mobile contact, PA1 input and output terminals for the circuit, PA1 this striker cooperating with this pushbutton so as to move this latter when it is attracted independently of the mobile part, and to bring it into a position where a locking device holds the switch in an open safety position.
Such switches are particularly used in protection apparatus where the power contacts serve at the same time for establishing and for the frequent breaking of the power supply circuits which are usually controlled by contactors.